The present invention relates to a projection display using a liquid crystal display element as image display element, forming an optical image by the liquid crystal display element in response to an image signal, and then projecting the optical image on a screen, and the like.
In a projection display, for example, such technique has been well-known as disclosed in JP-A-2005-31103, for installing an optical aperture for modulating the emitting light amount from a light source, and by controlling the light amount modulated by the optical aperture, in response to an image signal to enhance image contrast.